The present invention relates in general to network communications of processing systems. The invention relates to techniques for effecting communications between a network and multiple partitions of a data processing system employing a host-network interface. More particularly, the invention relates to a facility for retrieving data from a network adapter having an address resolution table shared by multiple communications stacks coupled to the network adapter. Specific parameters can be selectively retrieved and manipulated by an initiating communications stack.
Mainframe class data processing systems have hardware and software facilities that enable partitioning thereof. Such processing systems may be subdivided into multiple partitions whereby a user of a partition, or software executing in a partition, has the impression that the processing system is exclusively used by that application. Each partition has the appearance of being a separate and distinct processing system and may even run its own multi-tasking and multi-user operating systems independent from each other partition. An IBM Enterprise Systems Architecture (xe2x80x9cESAxe2x80x9d)/390 Mainframe Computer is an example of one such partitionable mainframe class data processing system. Partitioning thereof is described in, for example, various publications by International Business Machines Corporation, including xe2x80x9cIBM ESA/390 Principles of Operationxe2x80x9d, IBM Publication No. SA22-7201-02, December 1994, and in the xe2x80x9cIBM Enterprise System/9000 Processor Resource/Systems Manager Planning Guidexe2x80x9d, IBM Publication No. GA22-7123-11 (April 1994), which are both hereby incorporated herein by reference in their entirety.
Software executing in individual partitions within the mainframe class data processing system may require a network connection such as a local area network (xe2x80x9cLANxe2x80x9d) connection or a wide area network (xe2x80x9cWANxe2x80x9d) connection. This may be used to facilitate connectivity to users, or to application programs used in, for example, a client-server processing environment. Shown in FIG. 1 is a conventional configuration used to connect individual partitions, including the software running therein, to a LAN. The configuration includes a processing system 11 that has partitions 13, 15, 17, 19, 20 and 21.
Network connectivity for each partition of system 11 of FIG. 1 is achieved using separate network interfaces for each partition. For example, partition 13 is conventionally connected through channel connection 29 to an IBM 3172 Interconnect Controller 23 (with 8232 Channel Interface Attachment) that has, for example, a token ring or Ethernet LAN port 32 attached to LAN 37 thereby providing LAN connection 31. Network connectivity is accordingly directly provided between partition 13 and computers 43 and 45 on LAN 37 through the IBM 3172 23. However, according to conventional techniques, this configuration has no other direct logical or physical connections from any of the other partitions to LAN 37. To further note, each application within partition 23 must communicate with a different network port on IBM 3172 23. The IBM 3172 (having internal 8232 Channel Interface Attachment), is described in a publication entitled xe2x80x9c8232 LAN Channel Stationxe2x80x9d, Apr. 15, 1998, IBM Publication No. ZZ25-8577-0, that is incorporated herein by reference in its entirety.
The conventional software executing on IBM 3172s restricts direct logical connectivity to being between a single partition and its corresponding LAN. Thus, to facilitate direct connectivity from a computer 47 on a LAN 39 to both partition 17 and 21, multiple IBM 3172s would traditionally be used. Partition 17 is coupled to LAN 35 via channel connection 29xe2x80x2n, IBM 3172 25 and LAN port 34 thereby establishing LAN connection 33. Similarly, partition 21 is coupled to LAN 39 via channel connection 29xe2x80x3, IBM 3172 27, and LAN port 35 thereby establishing LAN connection 36.
An enhanced network interface for a mainframe class data processing system having multiple partitions and a port to a network is described in commonly assigned U.S. Pat. No. 5,740,438, which is hereby incorporated herein by reference in its entirety. Briefly summarized, this patent describes establishing a table which defines communications paths between the port to the network and at least two partitions of the multiple partitions. More specifically, each partition has at least one application executing therewithin and the communications paths are defined thereto. Data frames are passed between the network and the applications within the partitions through the port to the network and along the communications paths defined in the table such that the network communications is effected.
One embodiment of the network interface approach of U.S. Pat. No. 5,740,438 is depicted in FIG. 2. Shown is a partitionable mainframe class data processing system 11 (e.g., an IBM Enterprise System/9000) having an integral host-to-network interface (xe2x80x9cHNIxe2x80x9d) 51 that facilitates a LAN connection 55 from multiple partitions 13, 15, 17, 19, 20 and 21 to LAN 53 through LAN port 54. Each application in each partition may directly communicate with computers 61, 63 and 65 on LAN 53 through the single host-to-network interface 51 and single LAN port 54. The LAN shown is a token ring LAN; however, the system is equally applicable to other types of LANs such as, for example, Ethernet and Fiber Distributed Data Interface (xe2x80x9cFDDIxe2x80x9d). Further, the host-to-network interface may support multiple network connections by way of multiple network ports. For example, a WAN connection 57 comprising, for example, a Peer-to-Peer Protocol (xe2x80x9cPPPxe2x80x9d) connection may be established to a computer 59 through WAN port 56. Any mix of LAN and WAN connections among multiple ports of host-to-network interface 51 is possible.
The host-to-network connectivity techniques described above have certain limitations, particularly in an Ethernet environment where two different frame types are possible, i.e., Ethernet DIX and Ethernet 802.3. For client/server systems, Transmission Control Protocol (TCP)/Internet Protocol (IP) has become the leading protocol for network communications. Using Ethernet, when a client application running over TCP/IP wants to communicate with a server application, the application must specify one of the two existing Ethernet frame formats. The frame format must also be known by the server machine in order for the TCP/IP connection to be established and any data transfer to occur. Conventionally, in order to make sure that the client and server communicate using the same Ethernet frame formats, both the client and server must specify the specific frame format to be used in their appropriate configuration files. If the configuration files do not match, then the client/server application will not work properly.
The most common server TCP/IP environment today has the complete TCP/IP functionality on one platform. For example, reference xe2x80x9cTCP/IP Tutorial and Technical Overview,xe2x80x9d IBM Document No. GG24-3376-03 (December 1992). In this environment, one device driver exists in each partition for each LAN connection. Each device driver can specify a different Ethernet frame format, but will not support both frame formats. Thus, a different device driver is used for each of the two frame formats. In operation, a dedicated device driver of a partition of the host system takes care of providing both channel headers and media or LAN headers necessary for transmission of an IP packet across the LAN to a client coupled thereto.
With the above as background, the present invention is directed to enhancements to the state-of-the-art of network communications of multiple partitions employing a host-network interface, and in particular, to enhanced techniques for retrieving data from a network adapter having an address resolution table shared by multiple communications stacks of the multi-partition processing system.
Briefly summarized, the present invention comprises in one aspect a method for retrieving data in a communications environment comprising a network and a processing system coupled thereto across a network adapter. The processing system includes multiple communications stacks which communicate with the network across the network adapter. The network adapter has an address resolution table shared by the multiple communications stacks. The method includes: sending a command from a communications stack of the multiple communications stacks to the network adapter to retrieve specific data therefrom; and responsive to the command, extracting the specific data from the shared address resolution table at the network adapter for return to the communications stack sending the command.
Systems and program storage devices corresponding to the above-summarized method are also described and claimed herein.
The ability to integrate and manage heterogenous systems is important as the business world moves stronger into e-business. With today""s versions of gateways, the extended capabilities of the present invention increase the overall robustness of the communications network. The ability to dynamically monitor alterations, additions and deletions from the communications functions supported by the host and make necessary modifications in the system to reflect these changes is significant as this xe2x80x9cgatewayxe2x80x9d function is moved into the main system to act like an integrated internet/e-business machine. Further, a facility in accordance with the present invention can operate in conjunction with a variety of systems and be used in a heterogenous environment.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered part of the claimed invention.